Convert php function return values to true/false

Question

I first referred to this this, but it did not solve my problem.

I am having something like:

  $message .=   "\n\tWhether $testOutputDir is a directory:" . (!!is_dir($testOutputDir))
                . "\n\tWhether $outputDir is a directory:" . is_dir($outputDir)
                . "\n\tWhether $outputDir is readabale:" . is_readable($outputDir)
                ....

I just want to print something as follows:

       Whether /a is a directory: true
       Whether /b is a directory: true

But it prints as follows:

       Whether /a is a directory: 1
       Whether /b is a directory: 1

Any suggestions to solve this?

EDIT:

I could check func == 1 ? TRUE : FALSE. But I am expecting a simple cast or similar.

even if you do echo true, it will still print 1. so need a bool2str function — Fabricator
– Fabricator, Commented Jan 30, 2016 at 5:40
@Fabricator So I should use ternary operator. Is it the only way? — Gibbs
– Gibbs, Commented Jan 30, 2016 at 5:41

jbafford · Accepted Answer · 2016-01-30 05:59:09Z

In PHP, when a boolean value is converted to a string, you get '1' (for true) and '' (empty string, for false). If you want otherwise, you're going to have to explicitly convert the boolean value to a string.

There is no cast that will get you the result you want. One way to solve your problem would be to pass your value into this function:

function stringForBool($bool) {
    return ($bool ? 'true' : 'false');
}

//use like:
echo stringForBool(isReadable($outputDir));

You could also inline this function directly in your code, rather than calling it, but if you're using it more than a few times, that would become awfully repetitive.

Other answers suggest using json_encode(). While that certainly works (if you pass in a boolean value), you will not get the expected output if you pass in something that isn't exactly true or false. You can, of course, call json_encode((bool)$yourValue), that that will give you what you want, but (in my opinion) it's a little more magical and a little less explicit.

Will · Accepted Answer · 2016-01-30 05:44:21Z

0

You'd be stuck doing this:

is_dir($outputDir) ? 'true' : 'false'

Converting a bool to a string in PHP always converts it to "" or "1".

Now, this is a bit of a hack, but you can actually just use json_encode():

php > var_dump(json_encode(true));
string(4) "true"

edited Jan 30, 2016 at 5:44

answered Jan 30, 2016 at 5:42

Will

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1 Comment

jbafford Over a year ago

Not quite. (string)false will result in the empty string.

A l w a y s S u n n y · Accepted Answer · 2016-01-30 05:52:33Z

0

This may work,

echo json_encode(true);  // string "true"

echo json_encode(false); // string "false"

So,

 $message .=   "\n\tWhether $testOutputDir is a directory:" . json_encode(!!is_dir($testOutputDir))
                . "\n\tWhether $outputDir is a directory:" . json_encode(is_dir($outputDir))
                . "\n\tWhether $outputDir is readabale:" . json_encode(is_readable($outputDir))

edited Jan 30, 2016 at 5:52

answered Jan 30, 2016 at 5:44

A l w a y s S u n n y

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1 Comment

Gibbs Over a year ago

Hi Thanks, And what is the difference between your answer and ternary operator usage?

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